What's remarkable is that no other company -- no other oil company, no bank -- is close. Back in April, Forbes's annual Global 2000 list showed Exxon with a market cap of $407 billion, with Apple at $324 billion and Petro China (NYSE: PDT) at $321 billion. From there it dropped off to $240 billion (Chinese bank ICBC).

But Petro China shares have fallen sharply over the past two weeks, as have the shares of other oil companies, including Exxon Mobil. So any kind of recovery in the oil sector could make Apple's market-cap parity short-lived.

That particular horserace is of less interest than the larger picture, which shows technology challenging finance and energy as the most valuable industries -- at least in terms of total market cap -- in the world. The Forbes list from April shows the top 10 dominated by banks and energy conglomerates -- Petro China (No. 3), Chinese bank ICBC (No. 4), Petrobras-Petroleo Brasil (No. 5), Australian mining, oil and gas company BHP Billiton (No. 6), China Construction Bank (No. 7) and General Electric (No. 8).

This gives the tech sector more prominence among the world's most valuable companies than pharmaceuticals, retail and the food and beverage industries.

As mobile technology continues to infiltrate our daily and professional lives, most of the tech companies listed above are well-positioned to climb higher on the list. And why not? Technology is as critical to the global economy functioning as capital and energy.